Livestock farming satisfies the rapidly growing consumer driven demand for meat and dairy products and utilises approximately 70% of total global agricultural land for grazing and feed crop production. However, growing population and changing dietary preferences for meat and dairy will place increasing demand on global agricultural land.
Biotechnology offers some potential for meat substitutes to be produced more efficiently with lower environmental impact. The notable example is Mycoprotein (Quorn) produced by aerobic fermentation of glucose syrup. It is currently marketed as a (relatively expensive) healthy vegetarian alternative. It's relatively high cost is associated with use of refined feedstock (glucose syrup) and high fixed costs associated with investment cost in a dedicated modest capacity plant and energy costs associated with aerobic fermentation.
Livestock feed largely comprises of cereals (maize, wheat) providing the majority of carbohydrate, combined with protein enhancement (main source soymeal) to enhance the protein content for optimal nutrition. Approx 40% of grains are used as livestock feed. Agricultural yield of soybeans is typically significantly lower than cereals.
Fermentation from grain feedstock typically converts carbohydrates leaving a distiller dried grains with solubles (DDGS) residue concentrated in protein. This is used as a high protein component in livestock feed, however it's relatively low digestibility limits its mix ratio.
Global bioethanol production exceeds 60 million tepa, the 2 major sources being fermentation of cereals (particularly US maize converting approx 40% of its production) and Brazilian sugarcane. The economics (excluding government incentives) and environmental benefits of bioethanol from cereals (maize/wheat) are marginal. There are significant political issues associated with food v fuel pressures on land use and energy security.
U.S. Pat. No. 4,447,534 describes a process of producing ethanol using yeast where control of the growth conditions can increase the yield of the yeast and hence yeast derived unicellular protein.
Silva et al (Waste Management, 31 (2011), 108-114) describes a method of utilising the residue of spirit production and bio-ethanol for protein production by yeasts, such as Saccharomyces cerevisiae and Candida parapsilosis. The single cell protein form the yeast may be used as a source of supplemental protein for animal feed.
WO2009/079183 describes a process for improving the nutritional quality of a feed spent waste product which remains after fermentation of grain to produce alcohol. The spent waste product may be fermented with a microbe which is capable of breaking down cellulose and/or hemicellulose to one or more sugars and in turn using the sugar(s) to proliferate. As the microbes contain protein their proliferation serves to increase the protein content of the spent waste product. A variety of microbes including bacteria, yeasts and fungi are described, but there is no teaching of providing any single cell protein in isolation of the spent waste product.
It would be desirable to be able to provide a system which can be adapted to be able to produce both mycoprotein and ethanol in isolation of other material, whilst optionally being capable of varying the amount of each co-product based upon desired requirements, such as prevailing economic and/or socio-economic concerns.
It is amongst the object of the present invention to provide a method for the production, optionally co-production, of isolated mycoprotein and/or ethanol.